Fixed issue when parametrize_with_cases was used on case functions themselves (nesting/recursion). This was due to a lack of support of the place_as magic pytest attribute. Fixes #179

Author: Sylvain MARIE

pytest_cases/case_parametrizer_new.py

@@ -672,7 +672,20 @@ def _of_interest(x):  # noqa
                 cases_dct[gen_line_nb] = _m_item
 
         elif is_case_function(m, prefix=case_fun_prefix):
-            co_firstlineno = get_code_first_line(m)
+            try:
+                # read pytest magic attribute "place_as" to make sure this is placed correctly
+                m_for_placing = m.place_as
+            except AttributeError:
+                # nominal: get the first line of code
+                co_firstlineno = get_code_first_line(m)
+            else:
+                # currently we only support replacing inside the same module
+                if m_for_placing.__module__ != m.__module__:
+                    raise ValueError("Unsupported value for 'place_as' special pytest attribute on case function %s: %s"
+                                     ". Virtual placing in another module is not supported yet by pytest-cases."
+                                     % (m, m_for_placing))
+                co_firstlineno = get_code_first_line(m_for_placing)
+
             if cls is not None:
                 if isinstance(cls.__dict__[m_name], (staticmethod, classmethod)):
                     # nothing to do: no need to partialize a 'self' argument
@@ -693,6 +706,9 @@ def _of_interest(x):  # noqa
 
             if _case_param_factory is None:
                 # Nominal usage: put the case in the dictionary
+                if co_firstlineno in cases_dct:
+                    raise ValueError("Error collecting case functions, line number used by %r is already used by %r !"
+                                     % (m, cases_dct[co_firstlineno]))
                 cases_dct[co_firstlineno] = m
             else:
                 # Legacy usage where the cases generators were expanded here and inserted with a virtual line no

pytest_cases/tests/cases/issues/test_issue_179.py

@@ -0,0 +1,38 @@
+import pytest_cases as pytest
+
+
+@pytest.fixture
+def db_dep():
+    return None
+
+
+class CaseX:
+    def case_one(self, db_dep):
+        return 1
+
+    def case_two(self, db_dep):
+        return 2
+
+
+class CaseY:
+    @pytest.parametrize_with_cases("x", cases=CaseX, debug=True)
+    def case_x_one(self,db_dep,x):
+        return x, 1
+
+    @pytest.parametrize_with_cases("x", cases=CaseX, debug=True)
+    def case_x_two(self,db_dep,x):
+        return x, 1
+
+
+@pytest.parametrize_with_cases("x,y", cases=CaseY, debug=True)
+def test_nested_parametrize(x, y):
+    pass
+
+
+def test_synthesis(module_results_dct):
+    assert list(module_results_dct) == [
+        'test_nested_parametrize[x_one-one]',
+        'test_nested_parametrize[x_one-two]',
+        'test_nested_parametrize[x_two-one]',
+        'test_nested_parametrize[x_two-two]'
+    ]